First frost

Jacob Schor ND


It’s another beautiful day in Denver.  Blue skies and warm temperatures ahead.


Back in 1944 the first killing frost in Denver was on November 15th.  In theory the average date of our first freeze is October 7th.  In fact the US National Weather Sevice says our first freeze in Denver this year, 2016 was October 6th. [1]   Clearly that freeze didn’t affect my backyard as  I continue to gather fresh herbs from our garden.  Rosemary of course is cold tolerant, oregano and marjoram less so, but our basil is still green and fresh, with out a tinge of black frost burn.


I often stumble out to the garden in the early morning while it is still quite dark to gather herbs for a breakfast omlette.  I identify the herbs by touch.  Rosemary’s long needlelike leaves are the easiest, then just to the left are the tiny almost budlike marjoram leaves and then the basil just to the right.  The basil leaves are getting a bit tougher feeling with the cooler temperatures; but they are still soft to my touch.  There is a poppy plant just past them, sprouting up from the seeds left from the huge flowers that blossomed last summer.  Two poppy crops in one season.  I don’t recall that from years past.


While I savor my extended herb season, it does feel a bit odd this extended summer that doesn’t seem ready to end. Denver’s average date of our first snow is October 18th.  So we are running late this year. 


Lot’s of numbers are outside the norm this year.  In fact it seems that every month this year except September has set a worldwide temperature record. NOAA reported that August 2016 was the 16th straight month in a row to set a record global temperature.  They’ve been tracking temperatures since 1880. [2]


My sensation that picking basil in November is odd, isn’t so odd in light of how much global temperatures seem to have changed of late.


While NOAA’s records track back barely 135 years we can look at snowfall and temperature records dating back much further in Greenland.  During the 1960s

A United States Army outpost called Camp Century was set up on Greenland’s ice. While the claimed purpose was to do scientific investigations of Greenland’s ice, in reality the base was a cover for an extensive system of tunnels that housed intercontinental ballilstic missiles.  Greenland was the ‘cold’ of the Cold War.  As part of the ‘scientific cover’ of this ICBM missile base, scientists drilled and preserved core samples of the Greenland ice.  Hundreds of ice samples were collected, “… each about a yard and a half long and four inches in diameter. These sat around in a freezer in New Hampshire until Willi Dansgaard, … got hold of them.


“Dansgaard, who died in 2011, was an expert on the chemistry of precipitation. Presented with a sample of rainwater, he could, based on its isotopic composition, determine the temperature at which the precipitation had formed. This method, he realized, could also be applied to snow. Dansgaard was able to read the Camp Century core as a sort of almanac of Greenlandic weather. He could tell how the temperature had changed ice layer by ice layer, which is to say year by year.”


Thus we actually have fairly accurate temperature records going back many thousand years.  These records are perplexing.  “…in the midst of the last ice age, temperatures on Greenland had shot up by fifteen degrees in fifty years. Then they’d dropped again, almost as abruptly. This had happened not just once but many times……The temperature swings became known, after Dansgaard and a Swiss colleague, Hans Oeschger, as Dansgaard-Oeschger events. There have been twenty-five such events in the past hundred and fifteen thousand years………The Dansgaard-Oeschger (or D-O) events, which occurred at irregular intervals, have no apparent cause. The best explanation anyone has been able to offer is that the sheer complexity of the climate system renders it unstable—capable of flipping from one state to another….

All the D-O events predate the emergence of civilization, and this is probably no coincidence. In climatic terms, the past ten thousand years have been exceptionally stable. Go back further than that, and devastating shifts show up again and again. Somehow or other, our ancestors came through that chaos, but before the invention of agriculture people travelled light. They never stayed in one place long enough to develop complex societies and all that followed—cities, metallurgy, livestock, writing, money. When a D-O event occurred, bands of hunter-gatherers presumably picked up and moved on. Either that or they died out.” [3]


In these days when it seems that even discussing the weather can be a litmus test of political affiliations and where on the political spectrum one is, I hesitate to write further least I alienate some of my readers by apparently taking sides in a debate that elicits strong views as if this were a matter of religion.  In reality it is a matter of science, but of science that we do not fully understand yet.


With the smell of fresh basil still lingering on my hands, I have to wonder though whther we are we at the start of a Dansgaard-Oeschger event?  We should hope and pray that we are not.  Next to such a possibility theories of man made green house effect suddenly look benign and almost desirable.







New Yorker Oc 24, 2016